These stunning before-and-after photos are helping an Instagram star launch a fitness empire

The Instagram star and trainer has built a massive empire with over 4.6 million followers.

The 24-year-old Australian has become Instagram-famous with her Bikini Body Guides. She also recently launched an app that essentially puts her training in her fans' pockets.

The star has cultivated an online community that calls itself "Kayla's Army," largely by sharing impressive progress photos — or "transformations" — of the women who are committed to her program. It serves as visible inspiration.

These are some of the photos Itsines has shared:

The Bikini Body Guides are relatively simple.

Itsines provides her clients with three days of circuit-training routines that change every week. She encourages women to do sessions of "LISS" (low-intensity steady-state cardio) and later incorporate "HIIT" (high-intensity interval training) into their training regimen.

The "HELP" — Healthy Eating and Lifestyle Plan — guide features two weeks of diet plans.